Red Seal Industrial Electrician Practice Exam

What is the advantage of a three-phase electrical system over a single-phase system?

1. Lower installation cost

2. Simpler wiring configuration

3. Higher efficiency and power delivery

4. Easier maintenance

The correct answer is: Higher efficiency and power delivery

A three-phase electrical system has the advantage of higher efficiency and power delivery over a single-phase system, which stems from several fundamental characteristics of three-phase power. In a three-phase system, power is delivered continuously, as the three phases are offset by 120 degrees, resulting in a more balanced power supply that minimizes voltage fluctuations. This consistency allows for the ability to handle larger loads more effectively without the need for oversized conductors or equipment. Additionally, three-phase systems are inherently more efficient in their operation compared to single-phase systems, particularly in industrial applications that require high power. Motors and other devices connected to a three-phase system can run more smoothly and efficiently, reducing energy losses associated with starting and operating the machinery. Moreover, a three-phase system can deliver more power using less conductor material than a single-phase system, making it advantageous for transmitting electricity over long distances. The improved efficiency and power delivery also translate to less wear on equipment and lower operating costs in the long term, contributing to the overall performance benefits of a three-phase electrical system.